Fast Prefix Search in Little Space, with Applications

  • Djamal Belazzougui
  • Paolo Boldi
  • Rasmus Pagh
  • Sebastiano Vigna
Part of the Lecture Notes in Computer Science book series (LNCS, volume 6346)


A prefix search returns the strings out of a given collection S that start with a given prefix. Traditionally, prefix search is solved by data structures that are also dictionaries, that is, they actually contain the strings in S. For very large collections stored in slow-access memory, we propose extremely compact data structures that solve weak prefix searches—they return the correct result only if some string in S starts with the given prefix. Our data structures for weak prefix search use O(|S|logℓ) bits in the worst case, where ℓ is the average string length, as opposed to O(|S| ℓ) bits for a dictionary. We show a lower bound implying that this space usage is optimal.


Range Query Query Time Space Usage Query String Exit Node 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2010

Authors and Affiliations

  • Djamal Belazzougui
    • 1
  • Paolo Boldi
    • 2
  • Rasmus Pagh
    • 3
  • Sebastiano Vigna
    • 2
  1. 1.Université Paris DiderotParis 7France
  2. 2.Dipartimento di Scienze dell’InformazioneUniversità degli Studi di MilanoItaly
  3. 3.IT University of CopenhagenDenmark

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